Smoother Power

I had a Delta Contractors Table Saw from the 70's, a nice heavy saw for a contractors type. It was annoying because of vibration and buzzing. I ran it that way for a couple years.
I never managed to stop it from vibrating despite trying all sorts of things.
That is until I connected it up for 220v. It smoothed it out and was quietertoo.
I thought it was because I doubled the power pulses per revolution. Don't you pick up another phase when taking another line?
If not why did it smooth out so much? the original 120v wiring wasn't undersized. Can someone s'plain that please?
Just trying to learn more.

There are a lot of things that contribute to voltage drop besides the wire between the panel and the saw. For example, there's a certain amount of resistance in the motor winding, and you're stuck with it. Connections, plugs and switches all add to this. When you switch to 240 from 120, voltage drop is instantly cut in half. But this effect is amplified, because the faster the motor turns, the less current it needs, which further improves the voltage drop. So on a heavily loaded motor, switching to 240 will have a much larger impact than you might think.

I think the effect you were seeing is the result of less voltage drop in the wiring to your saw. All ac induction motors run slightly slower than their rated no-load speed. How much slower depends on the load and how much voltage is applied to them. On 120, your saw was probably slowing down enough under load to make the vibration more noticeable. Switching over to 240 would reduce the voltage drop, which in turn would make the motor turn faster under load.

In this case the wire size could be number 12 or even number 14 if the motor was the only thing on the circut. But if you go with the 240 volt you would spend more for the two pole circut breaker.

So the question remains, "do your get more power from a motor at a higher voltage"? In theory no, but if someone held a gun to my head and I had to choose I think I would say that the higher voltage motor may work better. Like Old has said, the electrical thing is just a theory, it seems to be a working theory but a theory none the less.

If the voltage to the motor drops in the wire some amount then the motor must draw more current to compensate in order to deliver that same amount of horse power. That added current in the motor winding will result in more heat in the motor as well as in the wire supplying it. Lost power in heat.

However the difference between a 120 volt circuit and a 240 volt circuit with no voltage drop in the supply wire will result in a nearly equal amount of horse power delivered for a given amount of electrical power delivered to the motor.

But as I showed in the compressor thread, any resistance in the supply wire results in 4 times the wasted power in a 120 volt circuit verses a 240 volt circuit. The thing to look at is at what point does that lost power become significant.

Regards
Gary

I meant to type 15" (15 feet).